Sustained economic development is impossible within an effectively closed system like Planet Earth. It is therefore more than a little surprising how much attention today is being focused on climate change and yet how little is being directed toward the potentially far more pressing issue of resource depletion. Fortunately these two challenges are inter-linked to the extent that most measures intended to combat climate change do involve using less resources and/or recycling precious materials. However, the fact that nobody has won mass public or political attention to the cause of using less resources because they will run out -- as opposed to using less resources because doing so may help us to combat climate change -- remains more than a little bizarre.

It cannot now reasonably be denied that the Earth's natural resources are currently being consumed at an increasing and totally unsustainable level. As a result, within a generation oil and many precious metals are likely to be scare and far more expensive. In 1972, an influential study called The Limits to Growth warned that humanity would start to exceed the carrying capacity of the Earth if we did not change our ways. Unfortunately, capitalism continued unabated, and 40 years later humanity's ecological footprint is at least 20 per cent beyond what the Earth can sustain. The figure below indicates this alarming the situation diagramatically. And if you look at this figure and think "well, we are still here -- so this must be wrong", just remember that any living system can exceed its limits for short period, but not indefinately.